JP5882507B1 - Photoelectric conversion element - Google Patents

Abstract

A photoelectric conversion element capable of improving durability is provided. The photoelectric conversion cell includes at least one photoelectric conversion cell, the photoelectric conversion cell including a pair of substrates, an oxide semiconductor layer provided on one of the pair of substrates, and an electrolyte provided between the pair of substrates. And an annular sealing portion that joins the pair of substrates, and at least one of the pair of substrates is inside the joining portion, the annular joining portion joined to the sealing portion, and sealed A plurality of first linear portions that are separated from each other, and two first linear portions among the plurality of linear portions are connected to each other. A first connecting portion, and when the substrate is viewed in the thickness direction, the first connecting portion is formed by extending the two linear portions to cross each other and is non-joined. A photoelectric conversion element formed by cutting out a corner opposite to the portion. [Selection] Figure 3

Description

  The present invention relates to a photoelectric conversion element.

  The dye-sensitized solar cell element is a next-generation photoelectric conversion element which has been developed by Gretzell et al. In Switzerland and has attracted attention because it has advantages such as high photoelectric conversion efficiency and low manufacturing cost.

  Such a photoelectric conversion element using a dye such as a dye-sensitized solar cell element generally includes at least one photoelectric conversion cell, and the photoelectric conversion cell is provided between a pair of substrates and a pair of substrates. An oxide semiconductor layer, an electrolyte provided between the pair of substrates, and an annular sealing portion that joins the pair of substrates are provided.

  As such a photoelectric conversion element, for example, a dye-sensitized solar cell disclosed in Patent Document 1 below is known. In this dye-sensitized solar cell, the thickness of the metal substrate used for the counter electrode, which is one of the pair of substrates, is 5 to 35 μm, so that the metal substrate can have flexibility. Therefore, even if a stress is applied to the metal substrate due to a change in pressure in the cell space, the stress is absorbed at the interface between the counter electrode and the electrolyte. For this reason, the stress in the interface of a counter electrode and a sealing part is relieved, As a result, the fall of the sealing capability of the sealing part with respect to a counter electrode is suppressed. Therefore, the dye-sensitized solar cell described in Patent Document 1 below can have excellent durability.

JP 2010-198823 A

  However, the dye-sensitized solar cell described in Patent Document 1 has the following problems.

  That is, the dye-sensitized solar cell described in Patent Document 1 still has room for improvement in terms of durability.

  This invention is made | formed in view of the said situation, and it aims at providing the photoelectric conversion element which can improve durability.

  As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by the following invention.

That is, the present invention includes at least one photoelectric conversion cell, and the photoelectric conversion cell is between a pair of substrates, an oxide semiconductor layer provided on one of the pair of substrates, and the pair of substrates. And an annular sealing portion that joins the pair of substrates, and at least one of the pair of substrates is joined to the sealing portion, and the joining A plurality of first linear portions and a plurality of linear portions that are separated from each other and have a non-joined portion that is inside the portion and is not joined to the sealing portion. A first connecting portion that connects the two first linear portions, and when the substrate is viewed in the thickness direction, the first connecting portion extends the two linear portions. the corner opposite the non-joining portion of the first cross-section made by intersecting with the thickness of the substrate It is formed by cutting out all along the direction, which is a photoelectric conversion element.

  In the photoelectric conversion element of the present invention, the internal pressure of the photoelectric conversion cell may change due to a change in ambient environmental temperature. When stress is repeatedly applied to the substrate, excessive stress may be applied to the interface between the substrate and the sealing portion. Here, in the photoelectric conversion cell of the photoelectric conversion element, when the substrate is viewed in the thickness direction, the first connecting portion is formed by extending the two first linear portions and intersecting each other. Is formed without cutting out the corner opposite to the non-joining portion, stress concentrates on the corner portion on the opposite side of the non-joining portion of the first intersecting portion, and the corner portion is It becomes easy to peel from the sealing part. On the other hand, according to the present invention, in the photoelectric conversion cell, when the substrate is viewed in the thickness direction, the first connecting portion extends the two first linear portions and intersects. It is formed by notching the corner on the opposite side to the non-joined portion in one intersection. Therefore, compared with the case where the corner on the opposite side to the non-joined portion in the intersecting portion is not cut out, the stress applied to the corner portion on the opposite side to the non-joined portion in the first connecting portion can be dispersed. . Therefore, the 1st connection part of a board | substrate becomes difficult to peel from a sealing part, and durability of a photoelectric conversion element provided with a photoelectric conversion cell can be improved.

  In the photoelectric conversion element, when the substrate is viewed in the thickness direction, the shape of the corner portion on the opposite side to the non-joining portion of the first connecting portion is arcuate, and the corner portion The curvature radius is preferably 0.05 to 6 mm.

  When the radius of curvature of the corner portion is within the above range, the effect of relaxing the stress concentration applied to the first connecting portion can be increased as compared with the case where the radius of curvature of the corner portion is less than 0.05 mm. Therefore, the durability of the photoelectric conversion element can be further improved. On the other hand, when the radius of curvature of the corner portion is within the above range, the effect of relaxing the stress concentration applied to the first connecting portion can be further increased and durability compared to the case where the radius of curvature of the corner portion exceeds 6 mm. The width of the sealing portion necessary for maintaining the property can be more sufficiently ensured.

  In the photoelectric conversion element, when the substrate is viewed in the thickness direction, the shape of the corner portion on the opposite side to the non-joining portion of the first connecting portion is linear, and the corner portion The length is preferably 0.05 to 4.0 mm.

  When the length of the corner portion is within the above range, the effect of relaxing the stress concentration applied to the first connecting portion can be further increased as compared with the case where the length of the corner portion is less than 0.05 mm. it can. On the other hand, when the length of the corner portion is within the above range, the effect of relaxing the stress concentration applied to the first connecting portion can be increased as compared with the case where the length of the corner portion exceeds 4.0 mm. The width of the sealing portion necessary for maintaining durability can be more sufficiently secured.

  In the photoelectric conversion element, the oxide semiconductor layer includes an inner portion and an annular outer portion surrounding the inner portion, and the outer portion includes a plurality of second linear portions separated from each other. A second connecting portion that connects two second linear portions of the plurality of second linear portions, and when the oxide semiconductor layer is viewed in the thickness direction, It is preferable that the second connecting portion is formed by cutting out a corner portion opposite to the inner portion of the second intersecting portion formed by extending and intersecting the two second linear portions. .

  In this case, when the oxide semiconductor layer is viewed in the thickness direction, the second connecting portion is opposite to the inner portion of the second intersecting portion formed by extending and intersecting the two second linear portions. Compared to the case where the corner portion on the side is not cut out, the second connecting portion of the oxide semiconductor layer is less likely to peel from the substrate, and the durability of the photoelectric conversion element including the photoelectric conversion cell is improved. be able to.

  In the photoelectric conversion element, when the sealing portion and the substrate are viewed in the thickness direction, the sealing portion protrudes on the opposite side of the first connecting portion of the substrate from the non-joining portion. Preferably it is.

  In this case, since the sealing width of the sealing portion can be sufficiently secured on the side opposite to the non-joining portion of the first connecting portion where stress is likely to concentrate, the durability of the photoelectric conversion element can be further sufficiently improved. it can.

  In the present invention, the “corner portion” refers to a boundary line between the first connecting portion and the corner portion.

  In the present invention, the “outer portion” of the oxide semiconductor layer refers to the thickness at a position of 1 mm from the peripheral edge of the oxide semiconductor layer when the oxide semiconductor layer is viewed from the thickness direction. .

  ADVANTAGE OF THE INVENTION According to this invention, the photoelectric conversion element which can improve durability is provided.

It is a top view which shows one Embodiment of the photoelectric conversion element of this invention. It is sectional drawing along the II-II line of FIG. It is the elements on larger scale of FIG. It is sectional drawing which cut | disconnected the photoelectric conversion element of FIG. 1 by the plane which passes along the sealing part. It is a fragmentary sectional view which shows one board | substrate among a pair of board | substrates of FIG. FIG. 5 is a partial view illustrating a modification of the oxide semiconductor layer in FIG. 4.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 is a plan view showing one embodiment of the photoelectric conversion element of the present invention, FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1, FIG. 3 is a partially enlarged view of FIG. 1 is a cross-sectional view of the photoelectric conversion element of FIG. 1 cut along a plane passing through a sealing portion, and FIG. 5 is a partial cross-sectional view showing one of the pair of substrates of FIG.

  As shown in FIG. 1 and FIG. 2, the photoelectric conversion element 100 is configured by one photoelectric conversion cell 60, and the photoelectric conversion cell 60 is provided on the first electrode substrate 10 and the first electrode substrate 10 as a substrate. A second electrode substrate 20 as an opposing substrate, an oxide semiconductor layer 30 provided on the first electrode substrate 10, an electrolyte 50 provided between the first electrode substrate 10 and the second electrode substrate 20, and a first An annular sealing portion 40 that joins the electrode substrate 10 and the second electrode substrate 20 is provided. The electrolyte 50 is filled in a cell space formed by the first electrode substrate 10, the second electrode substrate 20, and the sealing portion 40.

  The first electrode substrate 10 comprises a transparent substrate 11 and a transparent conductive substrate 15 composed of a transparent conductive film 12 as an electrode provided on the transparent substrate 11. Here, the peripheral part of the transparent conductive film 12 is sandwiched between the sealing part 40 and the transparent substrate 11 (see FIG. 2). Moreover, a part of the transparent conductive film 12 extends to the outside of the annular sealing portion 40, and the portion extending to the outside of the sealing portion 40 serves as a power extraction portion for taking out power. Function (see FIG. 1).

  The second electrode substrate 20 includes a bonding portion 20 a bonded to the sealing portion 40 and a non-bonding portion 20 b that is inside the bonding portion 20 a and is not bonded to the sealing portion 40. Here, the joining portion 20a is a first connecting portion that connects a plurality of first linear portions 23a that are separated from each other and two first linear portions 23a among the plurality of first linear portions 23a. 23b. As shown in FIG. 3, the first connecting portion 23b extends the two first linear portions 23a when the second electrode substrate 20 is viewed in the thickness direction. In the first intersecting portion 24 formed by intersecting, the corner portion 25 on the side opposite to the non-joined portion 20b is cut away. Further, as shown in FIG. 5, the second electrode substrate 20 includes a conductive substrate 21 and a catalyst layer 22 provided on the transparent conductive substrate 15 side of the conductive substrate 21 and contributing to the reduction of the electrolyte 50. Yes.

  The oxide semiconductor layer 30 is disposed inside the sealing portion 40. The sealing portion 40 and the oxide semiconductor layer 30 are separated from each other. A dye is adsorbed on the oxide semiconductor layer 30. The oxide semiconductor layer 30 includes an inner portion 31 and an annular outer portion 32 that surrounds the inner portion 31. As shown in FIG. 4, the outer portion 32 includes a plurality of (four in FIG. 3) second linear portions 32a that are spaced apart from each other, and two second lines out of the plurality of second linear portions 32a. It has the 2nd connection part 32b which connects the shape parts 32a. Here, the second connecting portion 32b of the outer portion 32 is a second intersection formed by extending and intersecting the two second linear portions 32a when the oxide semiconductor layer 30 is viewed in the thickness direction. The unit 33 is configured.

  Moreover, in the photoelectric conversion element 100, when the sealing part 40 and the 2nd electrode substrate 20 are seen in the thickness direction, it is on the opposite side to the non-joining part 20b among the 1st connection parts 23b of the 2nd electrode substrate 20. The sealing part 40 protrudes (refer FIG. 1).

  In the photoelectric conversion element 100, the internal pressure of the photoelectric conversion cell 60 may change due to a change in ambient environmental temperature. When stress is repeatedly applied to the second electrode substrate 20, excessive stress may be applied to the interface between the second electrode substrate 20 and the sealing portion 40. Here, in the photoelectric conversion cell 60 of the photoelectric conversion element 100, when the second electrode substrate 20 is viewed in the thickness direction, the first connecting portion 23b extends the two first linear portions 23a. If the corner 25 on the opposite side to the non-joining part 20b is formed in the first intersecting part 24 that is made to intersect, the corner on the opposite side to the non-joining part 20b in the first intersecting part 24 is formed. The stress is concentrated on the portion 24 a, and the corner portion 24 a is easily peeled off from the sealing portion 40. On the other hand, according to the photoelectric conversion element 100, when the second electrode substrate 20 is viewed in the thickness direction in the photoelectric conversion cell 60, the first connecting portion 23b has the two first linear portions 23a. Of the first intersecting portion 24 formed by extending and intersecting, the corner portion 25 opposite to the non-joined portion 20b is cut away. Therefore, compared with the case where the corner portion 25 on the opposite side to the non-joining portion 20b in the first intersecting portion 24 is not cut out, the corner portion 26 on the opposite side to the non-joining portion 20b in the first connecting portion 23b. The applied stress can be dispersed. Therefore, the 1st connection part 23b of the 2nd electrode substrate 20 becomes difficult to peel from the sealing part 40, and durability of the photoelectric conversion element 100 provided with the photoelectric conversion cell 60 can be improved.

  Moreover, in the photoelectric conversion element 100, when the sealing part 40 and the 2nd electrode substrate 20 are seen in the thickness direction, it is on the opposite side to the non-joining part 20b among the 1st connection parts 23b of the 2nd electrode substrate 20. The sealing part 40 protrudes. For this reason, since the sealing width | variety of the sealing part 40 can fully be ensured on the opposite side to the non-joining part 20b among the 1st connection parts 23b where stress tends to concentrate, durability of the photoelectric conversion element 100 is more fully secured. Can be improved.

  Next, the 1st electrode substrate 10, the 2nd electrode substrate 20, the oxide semiconductor layer 30, the sealing part 40, the electrolyte 50, and the pigment | dye are demonstrated in detail.

<First electrode substrate>
As described above, the first electrode substrate 10 is composed of the transparent conductive substrate 15, and the transparent conductive substrate 15 is composed of the transparent substrate 11 and the transparent conductive film 12 provided on the transparent substrate 11. Yes.

  The material which comprises the transparent substrate 11 should just be a transparent material, for example, As such a transparent material, glass, such as borosilicate glass, soda lime glass, white plate glass, quartz glass, polyethylene terephthalate (PET), for example Insulating materials such as polyethylene naphthalate (PEN), polycarbonate (PC), and polyethersulfone (PES). The thickness of the transparent substrate 11 is appropriately determined according to the size of the photoelectric conversion element 100 and is not particularly limited, but may be in the range of 50 to 40,000 μm, for example.

Examples of the material constituting the transparent conductive film 12 include conductive metal oxides such as tin-added indium oxide (ITO), tin oxide (SnO ₂ ), and fluorine-added tin oxide (FTO). The transparent conductive film 12 may be a single layer or a laminate of a plurality of layers made of different conductive metal oxides. When the transparent conductive film 12 is composed of a single layer, the transparent conductive film 12 is preferably composed of FTO because it has high heat resistance and chemical resistance. The thickness of the transparent conductive film 12 may be in the range of 0.01 to 2 μm, for example.

<Second electrode substrate>
As described above, the second electrode substrate 20 is provided on the conductive substrate 21 serving as the substrate and the second electrode, and the conductive substrate 21 is provided on the first electrode substrate 10 side and contributes to the reduction of the electrolyte 50. The catalyst layer 22 is provided.

  The conductive substrate 21 is made of a corrosion-resistant metal material such as titanium, nickel, platinum, molybdenum, tungsten, aluminum, and stainless steel. Alternatively, the substrate and the second electrode may be separated, and the insulating transparent substrate 11 described above may be formed of a laminate in which a transparent conductive film made of a conductive oxide such as ITO or FTO is formed as the second electrode. Here, when the conductive substrate 21 is formed of a laminate in which a transparent conductive film is formed on the transparent substrate 11, the transparent conductive film is transparent at least in the portion inside the sealing portion 40 of the second electrode substrate 20. It will be provided on the substrate 11. Here, the transparent conductive film may or may not be between the transparent substrate 11 and the sealing portion 40 in the bonding portion 20a. In addition, the thickness of the conductive substrate 21 is appropriately determined according to the size of the photoelectric conversion element 100 and is not particularly limited, but may be, for example, 0.005 to 4 mm.

  The catalyst layer 22 is composed of platinum, a carbon-based material, a conductive polymer, or the like. Here, carbon nanotubes are suitably used as the carbon-based material. In addition, the 2nd electrode substrate 20 does not need to have the catalyst layer 22 when the electroconductive board | substrate 21 has a catalyst function (for example, when containing carbon etc.).

  The shape of the corner portion 26 on the opposite side to the non-joining portion 20b in the first connecting portion 23b may be linear, or may be arcuate as shown in FIG.

  When the second electrode substrate 20 is viewed in the thickness direction, when the shape of the corner portion 26 on the opposite side to the non-joining portion 20b in the first connecting portion 23b is an arc shape, The curvature radius R1 is not particularly limited, but is preferably 0.05 to 6 mm, and more preferably 0.1 to 5 mm. When R1 is 0.05 to 6 mm, the effect of relaxing the stress concentration applied to the first connecting portion 23b can be increased as compared with the case where R1 is less than 0.05 mm. The durability of can be further improved. Further, when R1 is 0.05 to 6 mm, it is possible to increase the effect of relaxing the stress concentration applied to the first connecting portion 23b and to maintain durability as compared with the case where R1 exceeds 6 mm. The width of the sealing portion 40 can be more sufficiently ensured.

  Moreover, when the shape of the corner part 26 on the opposite side to the non-joining part 20b in the first connecting part 23b is a straight line, the length L1 is not particularly limited, but is 0.05 to 4.0 mm. It is preferable that it is 0.1-3.0 mm. In this case, compared with the case where L1 is less than 0.05 mm, the effect of relaxing the stress concentration applied to the first connecting portion 23b can be further increased, so that the durability of the photoelectric conversion element 100 is further improved. Can do. Moreover, when L1 is 0.05-4.0 mm, compared with the case where L1 exceeds 4.0 mm, the effect which relieve | moderates the stress concentration concerning the 1st connection part 23b can be enlarged, and durability is maintained. Therefore, the sufficient width of the sealing portion 40 can be ensured.

<Oxide semiconductor layer>
The oxide semiconductor layer 30 is composed of oxide semiconductor particles. Examples of the oxide semiconductor particles include titanium oxide (TiO ₂ ), zinc oxide (ZnO), tungsten oxide (WO ₃ ), niobium oxide (Nb ₂ O ₅ ), strontium titanate (SrTiO ₃ ), and tin oxide (SnO ₂ ). , Indium oxide (In ₃ O ₃ ), zirconium oxide (ZrO ₂ ), thallium oxide (Ta ₂ O ₅ ), lanthanum oxide (La ₂ O ₃ ), yttrium oxide (Y ₂ O ₃ ), holmium oxide (Ho ₂ O) ₃ ), bismuth oxide (Bi ₂ O ₃ ), cerium oxide (CeO ₂ ), aluminum oxide (Al ₂ O ₃ ), or two or more thereof.

  The thickness of the inner portion 31 of the oxide semiconductor layer 30 is usually 2 to 40 μm, preferably 10 to 30 μm.

<Sealing part>
Examples of the sealing portion 40 include thermoplastic resins such as modified polyolefin resins and vinyl alcohol polymers, and resins such as ultraviolet curable resins. Examples of modified polyolefin resins include ionomers, ethylene-vinyl acetic anhydride copolymers, ethylene-methacrylic acid copolymers, and ethylene-vinyl alcohol copolymers. These resins can be used alone or in combination of two or more.

<Electrolyte>
The electrolyte 50 includes, for example, a redox pair such as iodide ion (iodine ion) / polyiodide ion and an organic solvent. As an organic solvent, acetonitrile, methoxyacetonitrile, methoxypropionitrile, propionitrile, ethylene carbonate, propylene carbonate, diethyl carbonate, γ-butyrolactone, valeronitrile, pivalonitrile, glutaronitrile, methacrylonitrile, isobutyronitrile, Phenylacetonitrile, acrylonitrile, succinonitrile, oxalonitrile, pentanitrile, adiponitrile and the like can be used. Examples of the redox pair include iodide ions / polyiodide ions (for example, I ⁻ / I ₃ ⁻ ), and redox pairs such as bromide ions (bromine ions) / polybromide ions, zinc complexes, iron complexes, and cobalt complexes. It is done. The electrolyte 50 may be an ionic liquid instead of the organic solvent. As the ionic liquid, for example, a known iodine salt such as a pyridinium salt, an imidazolium salt, or a triazolium salt, and a room temperature molten salt that is in a molten state near room temperature is used. Examples of such room temperature molten salts include 1-hexyl-3-methylimidazolium iodide, 1-ethyl-3-propylimidazolium iodide, dimethylimidazolium iodide, ethylmethylimidazolium iodide, and dimethylpropyl. Imidazolium iodide, butylmethylimidazolium iodide, or methylpropyl imidazolium iodide is preferably used.

  The electrolyte 50 may be a mixture of the ionic liquid and the organic solvent instead of the organic solvent.

An additive can be added to the electrolyte 50. As the _{additive, LiI, I 2, 4-} t- butylpyridine, guanidinium thiocyanate, 1-methylbenzimidazole, 1-butyl-benzimidazole and the like.

Furthermore, as the electrolyte 50, a nanocomposite gel electrolyte which is a pseudo-solid electrolyte obtained by kneading nanoparticles such as SiO ₂ , TiO ₂ , and carbon nanotubes with the above electrolyte may be used, and polyvinylidene fluoride may be used. Alternatively, an electrolyte gelled with an organic gelling agent such as a polyethylene oxide derivative or an amino acid derivative may be used.

The electrolyte 50 includes an oxidation-reduction pair composed of iodide ions / polyiodide ions (for example, I ⁻ / I ₃ ⁻ ), and the concentration of polyiodide ions is preferably 0.006 mol / liter or less. In this case, since the concentration of polyiodide ions that carry electrons is low, the leakage current can be further reduced. For this reason, since an open circuit voltage can be increased more, a photoelectric conversion characteristic can be improved more. In particular, the concentration of polyiodide ions is preferably 0.005 mol / liter or less, more preferably 0 to 6 × 10 ⁻⁶ mol / liter, and 0 to 6 × 10 ⁻⁸ mol / liter. Is more preferable. In this case, when the photoelectric conversion element 100 is viewed from the light incident side of the conductive substrate 15, the color of the electrolyte 50 can be made inconspicuous.

<Dye>
Examples of the dye include a photosensitizing dye such as a ruthenium complex having a ligand containing a bipyridine structure, a terpyridine structure, or the like, an organic dye such as porphyrin, eosin, rhodamine, or merocyanine, or an organic-type such as a lead halide perovskite crystal. Examples include inorganic composite dyes. For example, CH ₃ NH ₃ PbX ₃ (X = Cl, Br, I) is used as the lead halide perovskite. Here, when a photosensitizing dye is used as the dye, the photoelectric conversion element 100 is composed of a dye-sensitized photoelectric conversion element, and the photoelectric conversion cell 50 is composed of a dye-sensitized photoelectric conversion cell. become.

  Among the above dyes, a photosensitizing dye composed of a ruthenium complex having a ligand containing a bipyridine structure or a terpyridine structure is preferable. In this case, the photoelectric conversion characteristics of the photoelectric conversion element 100 can be further improved.

  Next, a method for manufacturing the above-described photoelectric conversion element 100 will be described.

  First, a first electrode substrate 10 composed of a transparent conductive substrate 15 formed with a transparent conductive film 12 is prepared on one transparent substrate 11.

  As a method for forming the transparent conductive film 12, a sputtering method, a vapor deposition method, a spray pyrolysis method, a CVD method, or the like is used.

  Next, the oxide semiconductor layer 30 is formed over the transparent conductive film 12. The oxide semiconductor layer 30 is formed by printing and baking an oxide semiconductor layer forming paste containing oxide semiconductor particles. At this time, when the oxide semiconductor layer 30 is viewed in the thickness direction, the second connection portion 32b of the outer portion 32 extends the two second linear portions 32a and intersects. The unit 33 is configured.

  The oxide semiconductor layer forming paste includes a resin such as polyethylene glycol and a solvent such as terpineol in addition to the oxide semiconductor particles described above.

  As a method for printing the oxide semiconductor layer forming paste, for example, a screen printing method, a doctor blade method, a bar coating method, or the like can be used.

  The firing temperature varies depending on the material of the oxide semiconductor particles, but is usually 350 to 600 ° C., and the firing time also varies depending on the material of the oxide semiconductor particles, but is usually 1 to 5 hours.

  In this way, a working electrode is obtained.

  Next, the dye is adsorbed on the surface of the oxide semiconductor layer 30 of the working electrode. For this purpose, the working electrode is immersed in a solution containing a dye, and after the dye is adsorbed to the oxide semiconductor layer 30, excess dye is washed away with the solvent component of the solution and dried. A dye may be adsorbed on the oxide semiconductor layer 30. However, the dye may be adsorbed to the oxide semiconductor layer 30 by applying a solution containing the dye to the oxide semiconductor layer 30 and then drying the solution.

  Next, the electrolyte 50 is prepared.

  Next, the electrolyte 50 is disposed on the oxide semiconductor layer 30. The electrolyte 50 can be disposed by a printing method such as screen printing.

  Next, an annular sealing portion forming body is prepared. The sealing part forming body can be obtained, for example, by preparing a sealing resin film and forming one rectangular opening in the sealing resin film.

  Then, the sealing portion forming body is bonded onto the first electrode substrate 10. At this time, adhesion of the sealing portion forming body to the first electrode substrate 10 can be performed, for example, by heating and melting the sealing portion forming body.

  Next, a second electrode substrate forming body for forming the second electrode substrate 20 is prepared. And the 1st crossing part formed by crossing the 1st linear part 23a of joined part 20a joined to sealing part 40 in this 2nd electrode substrate formation object is specified. And the 1st connection part 23b is formed by notching the corner | angular part on the opposite side to the non-joining part 20b with respect to the specified 1st cross | intersection part. Thus, the second electrode substrate 20 is obtained. Here, the 1st connection part 23b can be formed, for example using a laser processing method or a wire processing method. When forming the 1st connection part 23b using a laser processing method, a pulse laser light source is used as a laser light source, for example.

The wavelength of the laser beam may be 1000 nm or more, preferably 1000-20.
It is 00 nm, More preferably, it is 1000-1200 nm.

The pulse width of the laser light is not particularly limited, but is usually 150 ns or less, preferably 100 ns or less. However, the pulse width of the laser light is preferably 5 ns or more.

  The irradiation energy per unit scanning distance of the laser light is preferably 0.01 to 0.3 J / mm, and more preferably 0.06 to 0.09 J / mm.

The number of times of cutting per location may be one time or a plurality of times, but one time is preferable from the viewpoint of production efficiency.

  Next, after arrange | positioning this 2nd electrode substrate 20 so that the opening of a sealing part formation body may be plugged up, it bonds together with a sealing part formation body. At this time, when the sealing portion 40 and the second electrode substrate 20 are viewed in the thickness direction, the sealing portion 40 is on the opposite side of the first connecting portion 23b of the second electrode substrate 20 from the non-joining portion 20b. It will protrude. At this time, the sealing portion forming body may be bonded to the second electrode substrate 20 in advance, and the sealing portion forming body may be bonded to the sealing portion forming body on the first electrode substrate 10 side. The bonding of the second electrode substrate 20 to the sealing portion forming body is performed, for example, under reduced pressure. As described above, the photoelectric conversion element 100 including one photoelectric conversion cell 60 is obtained.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the oxide semiconductor layer 30 is provided on the transparent conductive film 12 of the transparent conductive substrate 15 to receive light from this side, but the base material on which the oxide semiconductor layer 30 is formed is provided. In this case, an opaque material (for example, a metal substrate) may be used, a transparent material may be used as a base material for forming the second electrode substrate 20, and light may be received from the second electrode substrate 20 side. It does not matter as a structure.

  Moreover, in the said embodiment, when the oxide semiconductor layer 30 is seen in the thickness direction, the 2nd connection part 32b of the outer part 32 extends and crosses the 2nd 2 linear part 32a. As shown in FIG. 6, the second connecting portion 32b is a quadrangular second intersecting portion formed by extending and intersecting two second linear portions 32a. 33 may be formed by cutting out the corner 34 opposite to the inner portion 31. In this case, when the oxide semiconductor layer 30 is viewed in the thickness direction, the second connecting portion 32b extends from the two second linear portions 32a and intersects. Compared to the case where the corner portion 34 opposite to the inner portion 31 is not cut out, the second connecting portion 32b of the oxide semiconductor layer 30 is less likely to be peeled off from the first electrode substrate 10, and photoelectric conversion is performed. The durability of the photoelectric conversion element 100 including the cell 60 can be further improved.

  Here, the shape of the corner portion on the opposite side to the inner portion 31 in the second connecting portion 32b may be an arc shape as shown in FIG. 6 or a linear shape. Here, the “corner portion” refers to a boundary line between the second connecting portion 32 b and the corner portion 34.

  When the shape of the corner portion on the opposite side to the inner portion 31 of the second connecting portion 32b is an arc shape, the radius of curvature R2 is not particularly limited, but is preferably 0.1 to 5 mm. More preferably, it is 0.5-3 mm. When R2 is 0.1 to 5 mm, the effect of relieving stress concentration applied to the second connecting portion 32b can be increased as compared with the case where R2 is less than 0.1 mm. The durability of can be further improved. Moreover, when R2 is 0.1-5 mm, compared with the case where R exceeds 5 mm, an electric power generation area can be increased more and the photoelectric conversion characteristic of the photoelectric conversion element 100 can be improved more.

  When the shape of the corner portion on the side opposite to the inner portion 31 in the second connecting portion 32b is linear, the length L2 is not particularly limited, but is 0.14 to 4.2 mm. Is preferable, and it is more preferable that it is 0.3-3.0 mm. In this case, compared with the case where L2 is less than 0.14 mm, the effect of relaxing the stress concentration applied to the second connecting portion 32b can be increased, and therefore the durability of the photoelectric conversion element 100 can be further improved. Can do. Moreover, when L2 is 0.14-4.2 mm, compared with the case where L2 exceeds 4.2 mm, an electric power generation area can be increased more and the photoelectric conversion characteristic of the photoelectric conversion element 100 can be improved more. it can.

  Moreover, in the said embodiment, although the peripheral part of the transparent conductive film 12 is pinched | interposed by the sealing part 40 and the transparent substrate 11, the peripheral part of the transparent conductive film 12 is sealing part 40 except the said electric power extraction part. And the transparent substrate 11 may not be sandwiched.

  Moreover, in the said embodiment, when the sealing part 40 and the 2nd electrode substrate 20 are seen in the thickness direction, it seals on the opposite side to the non-joining part 20b among the 1st connection parts 23b of the 2nd electrode substrate 20. Although the part 40 protrudes, the sealing part 40 does not need to protrude on the opposite side to the non-joining part 20b among the 1st connection parts 23b of the 2nd electrode substrate 20. FIG.

  Moreover, in the said embodiment, although the photoelectric conversion element 100 is comprised by the one photoelectric conversion cell 60, the photoelectric conversion element may be provided with two or more photoelectric conversion cells 60. FIG.

  In the above embodiment, only the second electrode substrate 20 has the first connection portion 23b, but only the first electrode substrate 10 may have the first connection portion 23b, or the first electrode substrate. Both 10 and the second electrode substrate 20 may have the first connecting portion 23b.

  Furthermore, in the said embodiment, although the 1st electrode substrate 10 and the 2nd electrode substrate 20 are joined by the sealing part 40, between the 1st electrode substrate 10 and the 2nd electrode substrate 20, the electrolyte 50 is impregnated. In the case where the porous insulating layer is provided, the first electrode substrate 10 and the second electrode substrate 20 may not be joined by the sealing portion 40. However, in this case, it is necessary to provide a base material as a substrate on the side opposite to the first electrode substrate 10 with respect to the second electrode substrate 20 and to bond the base material and the first electrode substrate 10 at the sealing portion. It becomes.

  Hereinafter, the content of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

Example 1
First, a transparent conductive substrate formed by forming a transparent conductive film made of FTO having a thickness of 1 μm on a transparent substrate made of glass and having a thickness of 1 mm was prepared as a first electrode substrate.

  Next, the oxide semiconductor layer forming paste containing titania is screen-printed on the transparent conductive film of the first electrode substrate using a printing plate having a rectangular screen of 2 cm × 4 cm, and then 1 at 500 ° C. Baked for hours. At this time, the shape of the corner on the side opposite to the inner portion of the second connecting portion of the oxide semiconductor layer is a dot. Thus, a working electrode having an oxide semiconductor layer having a size of 2 cm × 4 cm was obtained.

  Next, the working electrode was immersed in the photosensitizing dye solution for a whole day and night, then taken out and dried, and the photosensitizing dye was adsorbed on the oxide semiconductor layer. A photosensitizing dye solution is prepared by dissolving a photosensitizing dye composed of Z907 in a mixed solvent in which acetonitrile and t-butanol are mixed at a volume ratio of 1: 1 so that the concentration is 0.2 mM. did.

  Next, an electrolyte was applied over the oxide semiconductor layer. As an electrolyte, a 3-methoxypropionitrile (MPN) solution containing 0.002M iodine and 0.6M 1,2-dimethyl-3-propylimidazolium iodide (DMPImI) was prepared.

  Next, the sealing part formation body for forming a sealing part was prepared. As the sealing part forming body, one sealing resin film made of 5.0 mm × 7.0 mm × 100 μm binel 14164 (trade name, manufactured by DuPont) is prepared, and the sealing resin film has a square shape. Obtained by forming shaped openings. At this time, the opening was made to have a size of 2.4 mm × 4.4 mm × 100 μm.

  And after mounting this sealing part formation body on a working electrode, the sealing part formation body was adhere | attached on the working electrode by heat-melting.

Next, a second electrode substrate forming body for forming a second electrode substrate was prepared. The second electrode substrate forming body was prepared by forming a catalyst layer made of platinum having a thickness of 10 nm on a 5.0 mm × 7.0 mm × 0.05 mm titanium foil by a sputtering method. And the 1st crossing part which crosses the 1st linear part of the joined part joined to the sealing part in the 2nd electrode substrate formation object is specified, and a non-junction part and the opposite side to the specified 1st crossing part The 1st connection part was formed by notching the corner | angular part. The first connecting portion was formed by laser processing so that the shape of the corner portion on the opposite side to the non-joined portion was an arc shape with a radius of curvature R1 = 0.5 mm. At this time, the laser light source used for laser processing, the pulse width of the laser light, and the irradiation energy per unit scanning distance were as follows.
(1) Laser light source Yb: fiber laser (oscillation wavelength: 1090 nm, product name: MD-F3000, Inc.)
KEYENCE made)
(2) Laser pulse width 50 ns
(3) Irradiation energy per unit scanning distance of laser light 0.06 J / mm
Thus, a counter electrode as a second electrode substrate was obtained.

  On the other hand, another sealing part forming body was prepared, and this sealing part forming body was adhered to the surface of the counter electrode facing the working electrode in the same manner as described above.

  And the sealing part formation body adhere | attached on the working electrode and the sealing part formation body adhere | attached on the counter electrode were made to oppose, and the sealing part formation bodies were piled up. And under pressure_reduction | reduced_pressure, the sealing part formation body was heat-melted, pressing. Specifically, the pressure of the space where the sealing portion forming body was heated and melted was 650 Pa. Thus, a sealing portion was formed between the working electrode and the counter electrode. At this time, the sealing part protruded on the opposite side to the non-joining part among the first connecting parts when the sealing part and the counter electrode were viewed in the thickness direction.

  A photoelectric conversion element composed of one photoelectric conversion cell was obtained as described above.

(Example 2)
Photoelectric conversion is performed in the same manner as in Example 1 except that the first connecting portion is formed by laser processing so that the shape of the corner portion on the side opposite to the non-joined portion is a straight line having a length L1 = 1.0 mm. An element was obtained.

(Example 3)
After the oxide semiconductor layer is screen-printed with a paste for forming an oxide semiconductor layer containing titania and then baked at 500 ° C. for 1 hour, the shape of the corner portion on the opposite side to the inner portion of the second connection portion is formed. A photoelectric conversion element was obtained in the same manner as in Example 1 except that it was formed to have an arc shape with a radius of curvature R2 = 0.5 mm. The screen printing is a printing having a screen in which the shape of a corner portion of a rectangle of 2 cm × 4 cm (a portion corresponding to the corner portion of the second connecting portion) is an arc shape having a curvature radius R2 = 0.5 mm. Made using the plate.

Example 4
After the oxide semiconductor layer is screen-printed with a paste for forming an oxide semiconductor layer containing titania and then baked at 500 ° C. for 1 hour, the shape of the corner portion on the opposite side to the inner portion of the second connection portion is formed. A photoelectric conversion element was obtained in the same manner as in Example 1 except that the length L2 was 0.71 mm. Note that the screen printing is a printing plate having a screen in which the shape of a rectangular corner portion (a portion corresponding to the corner portion of the second connecting portion) of 2 cm × 4 cm is a straight line having a length L2 = 0.71 mm. Made using.

(Examples 5 to 8)
After the oxide semiconductor layer is screen-printed with a paste for forming an oxide semiconductor layer containing titania and then baked at 500 ° C. for 1 hour, the shape of the corner portion on the opposite side to the inner portion of the second connection portion is formed. A photoelectric conversion element was obtained in the same manner as in Example 3 except that it was formed in an arc shape having a curvature radius R1 shown in Table 1. Note that the screen printing has a screen in which the shape of the corner portion of the rectangle of 2 cm × 4 cm (the portion corresponding to the corner portion of the second connecting portion) is an arc having the curvature radius R1 shown in Table 1. Performed using a printing plate.

(Examples 9 to 12)
Except that the first connecting portion is formed by laser processing so that the shape of the corner on the side opposite to the non-joined portion is a straight line having the length L1 shown in Table 1, the same as in Example 3. A photoelectric conversion element was obtained.

(Comparative Example 1)
Laser processing is not performed on the second electrode substrate forming body, the second electrode substrate forming body is used as it is as the second electrode substrate, and the shape of the corner portion of the first connecting portion on the side opposite to the non-joined portion is pointed out. A photoelectric conversion element was obtained in the same manner as in Example 1 except that.

<Durability evaluation>
The photoelectric conversion efficiency η0 was measured for the photoelectric conversion elements obtained in Examples 1 to 12 and Comparative Example 1. Next, the thermal cycle test was done about the photoelectric conversion element. In the thermal cycle test, the temperature around the photoelectric conversion element was raised from −40 ° C. to 90 ° C., held at 90 ° C. for 10 minutes, and then lowered from 90 ° C. to −40 ° C. 1 cycle was held for 10 minutes, and 200 cycles were performed. At this time, the rate of temperature increase and the rate of temperature decrease were both 10 ° C./min. And the photoelectric conversion efficiency (eta) 1 was measured again about the photoelectric conversion element after the heat cycle test. And the decreasing rate of the photoelectric conversion efficiency was computed based on the following formula.
Reduction rate of photoelectric conversion efficiency = 100 × (η0−η1) / η0
The results are shown in Table 1. In Table 1, when the rate of decrease in photoelectric conversion efficiency is 5% or less, “◎” is displayed, and when it is 5 to 10% or less, “○” is indicated as having sufficiently improved durability. However, when the rate of decrease in photoelectric conversion efficiency exceeds 10%, “x” is displayed because the durability is not sufficiently improved.

  From the results shown in Table 1, it was found that the photoelectric conversion elements of Examples 1 to 12 can improve the durability compared to the photoelectric conversion element of Comparative Example 1.

  As mentioned above, according to the photoelectric conversion element of this invention, it was confirmed that durability can be improved.

10: First electrode substrate (substrate)
20 ... Second electrode substrate (substrate)
20a ... Junction part 20b ... Non-joint part 23a ... 1st linear part 23b ... 1st connection part 24 ... 1st crossing part 25 ... Corner | angular part 26 ... The part of the corner on the opposite side to a non-joining part among 1st connection parts DESCRIPTION OF SYMBOLS 30 ... Oxide semiconductor layer 31 ... Inner part 32 ... Outer part 32a ... 2nd linear part 32b ... 2nd connection part 33 ... 2nd crossing part 34 ... Corner | angular part 40 ... Sealing part 50 ... Electrolyte 60 ... Photoelectric conversion cell 100: photoelectric conversion element

Claims (5)

Comprising at least one photoelectric conversion cell;
The photoelectric conversion cell is
A pair of substrates;
An oxide semiconductor layer provided on one of the pair of substrates;
An electrolyte provided between the pair of substrates;
An annular sealing portion that joins the pair of substrates,
At least one substrate of the pair of substrates has an annular bonding portion bonded to the sealing portion, and a non-bonding portion that is inside the bonding portion and is not bonded to the sealing portion,
The joint is
A plurality of first linear portions spaced apart from each other;
A first connecting portion that connects two first linear portions of the plurality of first linear portions;
When the substrate is viewed in the thickness direction, the first connecting portion is on the opposite side to the non-joining portion of the first intersecting portion formed by extending the two first linear portions and intersecting each other. A photoelectric conversion element formed by cutting out all corners of the substrate along the thickness direction of the substrate .   When the substrate is viewed in the thickness direction, the shape of the corner portion on the opposite side to the non-joined portion of the first connecting portion is an arc shape, and the radius of curvature of the corner portion is 0.05. The photoelectric conversion element according to claim 1, which is ˜6 mm.   When the substrate is viewed in the thickness direction, the shape of the corner portion on the opposite side to the non-joined portion of the first connecting portion is linear, and the length of the corner portion is 0.05. The photoelectric conversion element of Claim 1 which is -4.0 mm. The oxide semiconductor layer has an inner portion and an annular outer portion surrounding the inner portion;
The outer portion is
A plurality of second linear portions spaced apart from each other;
A second connecting part that connects two second linear parts among the plurality of second linear parts;
When the oxide semiconductor layer is viewed in the thickness direction, the second connecting portion extends from the two second linear portions and intersects the inner portion of the second intersecting portions. The photoelectric conversion element according to claim 1, wherein the photoelectric conversion element is formed by cutting out the opposite corner. The said sealing part protrudes on the opposite side to the said non-joining part among the said 1st connection parts of the said board | substrate when the said sealing part and the said board | substrate are seen in the thickness direction. The photoelectric conversion element as described in any one of these.

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